My homes are entirely different than this area has ever seen and is one of the most energy efficient(all electric & off grid) in the nation. In order to do that I will air seal the home VERY tight. The legal issues are that despite an air ventilation system, sealing in toxic chemicals that are not expelled by air, I do not use is the norm. As a matter of fact, there have been law suits around the country as a result of sealing in "sick homes". I designed the home properly with the IAQ (Indoor air quality tested by third party). I have already started telling my clients if they want to change the design to bring in toxic materials they will have to sign a release of liability.